But some of the powershell script code can not be executed, because of checksum error.

Some specific character sequece with ANSI coding is automatically replased other double byte character on Japanse Windows. ANSI coding is mapped ro Shift-JIS coding on Japanese WIndows. See attached screen shot. In order to avoid this, please save all of the PowerShell source file with UTF8, and regenerate signature. Would you do this for us?